Conventionally, a technology to decorate (carve decorative patterns on) a molded body, such as a case used for home electric appliances, for example, mobile phones and personal computers, with a film decorative material expressing characters and/or drawing patterns, has been actively used.
As this decorative material, for example, a decorative material disclosed in Patent Literature 1 (“transfer material” in the patent literature) is known, and as the configuration, one where a transfer layer expressing characters and/or drawing patterns is arranged to be peelable from a support substrate (“substrate sheet” in Patent Literature 1) on the support substrate is known (for example, see Patent Literature 1 and FIG. 2). A molded body can be decorated by attaching this transfer layer to the molded body and by peeling the support substrate.
The transfer layer is composed of a plurality of layers, and a configuration containing a synthetic resin and pigments and containing a pattern layer(s) expressing characters and/or drawing patterns is known (for example, see Paragraph [0020] of Patent Literature 1; “drawing pattern” may be expressed as “printed layer” in Patent Literature 1). Further, in order to add metallic luster to the characters and/or drawing patterns drawn on the pattern layer to the transfer layer, a configuration where a film-like metallic layer (metallic thin film layer) is partially established within the transfer layer is also known, and in addition, as the drawing pattern layer expressing the characters and/or drawing patterns, the configuration composed with a film-like metallic layer is known (for example, see Paragraph [0021] of Patent Literature 1).
As the metallic layer, a configuration of the decorative material adopting a metallic layer having radio wave permeability (hereafter, referred to as “radio wave permeable metallic layer”) is known, and for example, a transfer material (decorative material) having an island structure of metallic deposited layer (radio wave permeable metallic layer) is disclosed in Patent Literature 2 as a decorative material having a radio wave permeable metallic layer.
Then, when the decorative material having a configuration partially containing the metallic layer, such as a radio wave permeable metallic layer, within the transfer layer is manufactured, as a method for forming the metallic layer, such as the radio wave permeable metallic layer, a method via a so-called etching process and another method via a so-called water washing process are known.
For example, as the method via the etching process, mainly, a method containing (1) a process to form a metallic layer over an entire principal surface of the underlayer; (2) a process to form a mask layer (referred to as “resist layer” in Paten Literature 1) on/over a partial region (a metallic luster portion) to be remained among the metallic layer; and (3) a process to remove the partial region of the metallic layer not to be covered with the mask layer after the etching is performed using acid or alkali is known (for example, see Paragraph [0021] of Patent Literature 1).
Further, as the method via the water washing treatment process, mainly, a method containing (1) a process to form a solvent-soluble resin layer (a water-soluble resin layer) in a portion not requiring a metallic layer out of the underlayer; (2) a process to form a metallic layer over the entire surface of the underlayer partially coated with the solvent-soluble resin layer so as to cover the solvent-soluble resin layer, as well; and (3) a process to remove any unnecessary metallic layer along with the solvent-soluble resin layer by washing with water or a solution, which is a solvent, is known (for example, see Paragraph [0021] of Patent Literature 1).
In the case of the method via the water washing treatment process, it is difficult to completely remove a water-soluble resin layer, and in the decorative material formed while a residue of the water-soluble resin layer that has been swelled due to containing moisture remains, corrosion of the metallic layer progresses due to the moisture or pinholes may occur due to the swelling. In the meantime, since no water-soluble resin layer is used in the case of the method via the etching process, it is hard for corrosion of the metallic layer and pinholes to progress. Consequently, in this viewpoint, it can be said that the method via the etching process is a superior forming method to the method via the water washing treatment process.    [Patent Literature 1] Japanese Patent Application Laid-Open No. H8-324196    [Patent Literature 2] Japanese Patent Application Laid-Open No. S60-168689